The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A nacelle generally has a tubular structure comprising an air intake upstream from the turbojet engine, a middle section designed to surround a fan of the turbojet engine, a downstream section housing a thrust reverser device and designed to surround the combustion chamber of the turbojet engine, and generally ends with a jet nozzle whereof the outlet is situated downstream from the turbojet engine.
Modern nacelles are designed to house a dual flow turbojet engine capable of using the rotating fan blades to generate a hot air flow (also called primary flow) coming from the combustion chamber of the turbojet engine, and a cold air flow (secondary flow) that circulates outside the turbojet engine through an annular passage, also called tunnel, formed between the fairing of the turbojet engine and an inner wall of the nacelle. The two air flows are discharged from the turbojet engine through the rear of the nacelle.
During landing of the aircraft, the role of a thrust reverser device is to improve the braking capacity of that aircraft by reorienting at least part of the thrust generated by the turbojet engine forward. During this phase, the reverser obstructs the cold flow tunnel and orients the latter toward the front of the nacelle, thereby generating a counterthrust that is added to the braking of the wheels of the airplane.
The means used to perform this reorientation of the cold flow vary depending on the type of reverser. However, in all cases, the structure of a thrust reverser device comprises moving parts movable on the one hand between a deployed position in which they open a passage in the nacelle designed for the deflected flow, and on the other hand a retracted position in which they close that passage.
These moving elements can perform a deflecting function or simply serve to activate other deflecting means.
In the case of a cascade reverser, the thrust reverser device includes cascade vanes serving to reorient the flow of air, associated with reverser flaps and cowls that are translatable in a direction substantially parallel to the longitudinal axis of the nacelle.
The moving cowls serve to slide, so as to expose or cover said cascade vanes. The reverser flaps form blocking doors that can be activated by the sliding of the cowl, closing the tunnel downstream from the vanes, so as to optimize the reorientation of the cold air flow.
Furthermore, aside from its thrust reversal function, the sliding cowl belongs to the rear section and has a downstream side forming the jet nozzle serving to channel the discharge of the flows of air.
This nozzle provides the power necessary for propulsion while imparting a speed to the discharge flows and modulates the thrust by varying its output section in response to variations of the adjustment of the power of the engine and the flight conditions.
It is known, in particular from document WO 2009/029401, to provide, on the nozzle section situated just behind a moving cowl, a nozzle flap mounted movable between a closed position and at least one open position in which said nozzle flap opens a leakage passage toward the outside of the nozzle. In this document, the leakage passages in the nozzle are obtained by translating the nozzle flaps using specific cylinders dedicated to movement of the flaps and separate from the cylinders used to move the moving cowls and therefore allow the deployment of the thrust reverser device.
The interest of using such moving flaps is to be able to adapt the optimal section of the jet nozzle as a function of the different flight phases, i.e., the takeoff, cruising, and landing phases of the airplane.
The main drawback of this type of nacelle is related to the use of actuating cylinders for the moving cowls and additional actuating cylinders for the nozzle flaps, the presence of these additional cylinders causing excess weight for the nacelle and also causing increased complexity to implant such cylinders in a cluttered and narrow environment.
The state of the art may also be illustrated by the teaching of documents U.S. Pat. No. 3,779,010 and US 2003/126856, which each disclose a turbojet engine nacelle including a thrust reverser device with a moving cowl whereof the translation is controlled using an actuator, and with a reverser flap.